In my never ending quest to keep my aging 2004 WRX functional, I’ve started to look into my wobbling boost pressures. One suggestion I heard was that, after hundreds of thousands of miles, it’s unlikely that the original boost control solenoid is still working at peak efficiency. That seems pretty reasonable, considering that it has been working non-stop for every mile.

The problem is that I can’t find the OEM part number for the solenoid. I’m not looking for an after-market part as I don’t want to retune. I’m just trying to find the OEM part and do an in-place replacement.

I’ve been through my standard part websites but the diagrams and part selections all seem to be missing the solenoid itself.

NOTE: I’m not looking for the blow-off valve. That seems to be working just fine (and is a different part).

1 Answer
1

Assuming you're running a totally vanilla WRX it will have a 2 port boost solenoid.

For a 2004-06 car that is DENSO part # 16102AA360:

For those with an 02-03 car it's DENSO part # 16102AA160:

Which is basically the same but the electrical connector is on the other side.

Before replacing it might be worth giving it a clean (the genuine OEM ones aren't particularly cheap!) - to do that take it off the car, squirt some brake cleaner (make sure it's the non-chlorinated stuff) into both ports and actuate it a couple of times. Let it dry (or dry off with an air duster) and re-fit it.

If your car has any of the Prodrive upgrades it might have the 3 port Prodrive BCS fitted (don't have the part no. to hand for that one I'm afraid), should be fairly obvious visually if this is the case though.

PS: If you're taking the BCS off to clean or replace it make sure you don't lose the restrictor pill - otherwise you'll be left getting mechanical boost only!

What I see when I look for that part number is that a lot of sites list it as the EGR valve as a part of the emission system. That’s all kinds of the wrong answer for this application....
– Bob Cross♦Jan 22 at 15:42

@BobCross it's definitely the right part, I'll update the answer with a pic
– motosubatsuJan 22 at 15:46

For the 2004 WRX, it appears that the right part might end in 360 (not 160 as on the 2002-2003).
– Bob Cross♦Jan 22 at 16:22

@BobCross Interesting.. AFAIK they stayed the same until '07, had a look at the '360 though and it seems that the electrical connector is on the other side
– motosubatsuJan 22 at 16:33